Rectangular cartons having foldable end flaps are used by Frito-Lay, Inc., the assignee of the present invention, and others to package bags of snack foods such as potato chips, corn chips, corn puffs and the like for shipment. Typically, the cartons are erected by hand and the bags of product are placed in the carton manually, afterwhich a manual fold is used to close the top of the carton. It is frequently desirable that the cartons be reused, so that destructive closure means for bottom and top closures are to be avoided. Thus, typical automatic devices for closing cartons having closable end flaps which utilize glue, staples, tape or other destructive closure means are not suitable for applications wherein the carton is expected to be collapsed after the bags of product are removed and returned for reuse. At the same time, the manual process of erecting, filling and closing cartons is costly.
Efforts have been made to automate the packaging of light weight fragile products such as bags of snack foods. An example of an automatic packaging device is disclosed in U.K. Patent Application 2,200,093 to Bishopbarn Ltd. entitled "PACKAGE HANDLING METHOD AND APPARATUS." However, such disclosures do not include an automated device for erecting a carton and creating a secure, reusable bottom closure. Accordingly, full automation of carton erection, wherein a reusable folded bottom closure is formed, the contents are placed in the carton and a folded top closure is made, remains lacking in the art.
One alternative known in the art is the use of folded cartons having an automatic opening and closing permanent bottom that is simultaneously formed when the carton sides are expanded to the desired geometry. The use of an automatic permanent bottom produces an excessive cost as the carton materials are significantly greater than a typical carton design, which reduces the feasibility of automation. Further, an automatic opening and closing permanent bottom case typically includes several additional folds within the flattened carton that add undue thickness to a portion of the folded carton, making stacking and handling of folded permanent bottom cartons awkward and problematic, especially when such cartons are intended to be collapsed, stored and returned for reuse.
It is desirable to utilize a simple box design with bottom fold closures to produce a secure bottom closure. Top folding closures and various automated methods for producing top closures are known in the prior art. U.S. Pat. No. 4,584,818 to Plaskett entitled "APPARATUS FOR AUTOMATICALLY CLOSING L-SLIDE LOCK CARTONS" as well as U.S. Pat. No. 4,656,810 to Plaskett entitled "APPARATUS FOR AUTOMATICALLY LOCKING L-SLIDE LOCK CARTONS" demonstrate automated devices that fold and insert a final flap into the L-shaped slots of adjacent end flaps and provide a secure top closure. It is noted, however, that the carton described in these patents is presented to the top closure mechanism with all flaps in a folded horizontal position perpendicular to the side walls of the carton.
What is lacking in the prior art is a means to provide automated fold closures for bottom end flaps of an open reusable carton.
Hence, it is an object of the present invention to provide a method for closing the bottom end flaps of a rectangular carton.
This and other objects of the present invention will be obvious to one skilled in the art from the below description of the invention and the attached drawings.